Why does the Volkswagen Magotan engine shake slightly when just started?

[JadeAnn]

There are several reasons for the Magotan's cold start shaking: 1. Low ignition energy: When the car starts cold, the temperature inside the engine is insufficient, and the temperature of fuel and lubricating oil is not enough. After long-term use, the spark plug's ignition gap increases, leading to reduced ignition energy, affecting power performance and causing the car to shake. 2. Carbon deposits on valves and intake passages: If carbon deposits occur on the valves and intake passages inside the engine, the carbon deposits can absorb an appropriate amount of fuel, causing the ECU to make incorrect judgments and fail to achieve the required power performance, resulting in shaking. 3. Inappropriate mixture ratio: Incorrect adjustment of the air-fuel mixture ratio and non-functioning oxygen sensor. In this case, the ECU makes judgment errors, leading to inaccuracies in controlling the air-fuel mixture and ignition timing through the actuators, reducing the car's power output and causing shaking.

[VonChristopher]

My Magotan has been running for over five years, and I've also experienced occasional shaking during cold starts. The main reason is that the engine oil hasn't fully lubricated yet, especially noticeable in low winter temperatures. Additionally, aging spark plugs or faulty ignition coils can cause misfires in individual cylinders, making the car body shake severely. Carbon buildup in the fuel injectors can also lead to uneven fuel delivery, causing an imbalance in the air-fuel mixture during cold starts and resulting in shaking. I recommend first checking if the engine oil needs changing, as a clogged fuel filter can also cause unstable fuel supply. If the shaking stops after the engine idles smoothly, there's generally no need to worry—just use fuel additives regularly to clean carbon deposits.

[MacWeston]

The shaking right after startup could be caused by aging engine mount bushings. Over time, the rubber components harden and lose their vibration-damping effectiveness. Another possibility is an air intake leak leading to an overly lean air-fuel mixture, or delayed feedback from the oxygen sensor affecting the air-fuel ratio, resulting in unstable RPMs and shaking during cold starts. I'm particularly mindful of my warm-up routine - I always wait about 30 seconds after starting for the RPMs to settle before driving. Additionally, I regularly check if the air filter is too dirty, as a clogged filter restricting airflow can also cause shaking.

[ElijahFitz]

Common causes of startup shaking include insufficient battery voltage affecting the ignition system, and inadequate fuel pump pressure leading to insufficient fuel injection. Additionally, deviations in the crankshaft position sensor signal can affect ignition timing, especially in high-mileage vehicles. The methods I've used to address this include regularly cleaning throttle valve carbon deposits and checking whether the alternator is generating electricity properly. Occasionally using higher-octane gasoline can also help alleviate the issue.